/*
 * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */

package com.sun.source.util;

import java.lang.reflect.Method;

import javax.annotation.processing.ProcessingEnvironment;
import javax.lang.model.element.AnnotationMirror;
import javax.lang.model.element.AnnotationValue;
import javax.lang.model.element.Element;
import javax.lang.model.element.ExecutableElement;
import javax.lang.model.element.TypeElement;
import javax.lang.model.type.DeclaredType;
import javax.lang.model.type.ErrorType;
import javax.lang.model.type.TypeMirror;
import javax.tools.Diagnostic;
import javax.tools.JavaCompiler.CompilationTask;

import com.sun.source.tree.CatchTree;
import com.sun.source.tree.ClassTree;
import com.sun.source.tree.CompilationUnitTree;
import com.sun.source.tree.MethodTree;
import com.sun.source.tree.Scope;
import com.sun.source.tree.Tree;

/**
 * Bridges JSR 199, JSR 269, and the Tree API.
 *
 * @author Peter von der Ah&eacute;
 */
@jdk.Exported
public abstract class Trees {

  /**
   * Gets a Trees object for a given CompilationTask.
   *
   * @param task the compilation task for which to get the Trees object
   * @throws IllegalArgumentException if the task does not support the Trees API.
   */
  public static Trees instance(CompilationTask task) {
    String taskClassName = task.getClass().getName();
    if (!taskClassName.equals("com.sun.tools.javac.api.JavacTaskImpl")
        && !taskClassName.equals("com.sun.tools.javac.api.BasicJavacTask")) {
      throw new IllegalArgumentException();
    }
    return getJavacTrees(CompilationTask.class, task);
  }

  /**
   * Gets a Trees object for a given ProcessingEnvironment.
   *
   * @param env the processing environment for which to get the Trees object
   * @throws IllegalArgumentException if the env does not support the Trees API.
   */
  public static Trees instance(ProcessingEnvironment env) {
    if (!env.getClass().getName()
        .equals("com.sun.tools.javac.processing.JavacProcessingEnvironment")) {
      throw new IllegalArgumentException();
    }
    return getJavacTrees(ProcessingEnvironment.class, env);
  }

  static Trees getJavacTrees(Class<?> argType, Object arg) {
    try {
      ClassLoader cl = arg.getClass().getClassLoader();
      Class<?> c = Class.forName("com.sun.tools.javac.api.JavacTrees", false, cl);
      argType = Class.forName(argType.getName(), false, cl);
      Method m = c.getMethod("instance", new Class<?>[]{argType});
      return (Trees) m.invoke(null, new Object[]{arg});
    } catch (Throwable e) {
      throw new AssertionError(e);
    }
  }

  /**
   * Gets a utility object for obtaining source positions.
   */
  public abstract SourcePositions getSourcePositions();

  /**
   * Gets the Tree node for a given Element.
   * Returns null if the node can not be found.
   */
  public abstract Tree getTree(Element element);

  /**
   * Gets the ClassTree node for a given TypeElement.
   * Returns null if the node can not be found.
   */
  public abstract ClassTree getTree(TypeElement element);

  /**
   * Gets the MethodTree node for a given ExecutableElement.
   * Returns null if the node can not be found.
   */
  public abstract MethodTree getTree(ExecutableElement method);

  /**
   * Gets the Tree node for an AnnotationMirror on a given Element.
   * Returns null if the node can not be found.
   */
  public abstract Tree getTree(Element e, AnnotationMirror a);

  /**
   * Gets the Tree node for an AnnotationValue for an AnnotationMirror on a given Element.
   * Returns null if the node can not be found.
   */
  public abstract Tree getTree(Element e, AnnotationMirror a, AnnotationValue v);

  /**
   * Gets the path to tree node within the specified compilation unit.
   */
  public abstract TreePath getPath(CompilationUnitTree unit, Tree node);

  /**
   * Gets the TreePath node for a given Element.
   * Returns null if the node can not be found.
   */
  public abstract TreePath getPath(Element e);

  /**
   * Gets the TreePath node for an AnnotationMirror on a given Element.
   * Returns null if the node can not be found.
   */
  public abstract TreePath getPath(Element e, AnnotationMirror a);

  /**
   * Gets the TreePath node for an AnnotationValue for an AnnotationMirror on a given Element.
   * Returns null if the node can not be found.
   */
  public abstract TreePath getPath(Element e, AnnotationMirror a, AnnotationValue v);

  /**
   * Gets the Element for the Tree node identified by a given TreePath.
   * Returns null if the element is not available.
   *
   * @throws IllegalArgumentException is the TreePath does not identify a Tree node that might have
   * an associated Element.
   */
  public abstract Element getElement(TreePath path);

  /**
   * Gets the TypeMirror for the Tree node identified by a given TreePath.
   * Returns null if the TypeMirror is not available.
   *
   * @throws IllegalArgumentException is the TreePath does not identify a Tree node that might have
   * an associated TypeMirror.
   */
  public abstract TypeMirror getTypeMirror(TreePath path);

  /**
   * Gets the Scope for the Tree node identified by a given TreePath.
   * Returns null if the Scope is not available.
   */
  public abstract Scope getScope(TreePath path);

  /**
   * Gets the doc comment, if any, for the Tree node identified by a given TreePath.
   * Returns null if no doc comment was found.
   *
   * @see DocTrees#getDocCommentTree(TreePath)
   */
  public abstract String getDocComment(TreePath path);

  /**
   * Checks whether a given type is accessible in a given scope.
   *
   * @param scope the scope to be checked
   * @param type the type to be checked
   * @return true if {@code type} is accessible
   */
  public abstract boolean isAccessible(Scope scope, TypeElement type);

  /**
   * Checks whether the given element is accessible as a member of the given
   * type in a given scope.
   *
   * @param scope the scope to be checked
   * @param member the member to be checked
   * @param type the type for which to check if the member is accessible
   * @return true if {@code member} is accessible in {@code type}
   */
  public abstract boolean isAccessible(Scope scope, Element member, DeclaredType type);

  /**
   * Gets the original type from the ErrorType object.
   *
   * @param errorType The errorType for which we want to get the original type.
   * @return javax.lang.model.type.TypeMirror corresponding to the original type, replaced by the
   * ErrorType.
   */
  public abstract TypeMirror getOriginalType(ErrorType errorType);

  /**
   * Prints a message of the specified kind at the location of the
   * tree within the provided compilation unit
   *
   * @param kind the kind of message
   * @param msg the message, or an empty string if none
   * @param t the tree to use as a position hint
   * @param root the compilation unit that contains tree
   */
  public abstract void printMessage(Diagnostic.Kind kind, CharSequence msg,
      com.sun.source.tree.Tree t,
      com.sun.source.tree.CompilationUnitTree root);

  /**
   * Gets the lub of an exception parameter declared in a catch clause.
   *
   * @param tree the tree for the catch clause
   * @return The lub of the exception parameter
   */
  public abstract TypeMirror getLub(CatchTree tree);
}
